The S-ICD System™ from Cameron Health, Inc., and Boston Scientific Corporation presents a new opportunity in cardiac rhythm management to reduce the complications associated with transvenous defibrillator systems. The defibrillator system itself may be implanted subcutaneously without accessing the vasculature or touching the heart.
An illustration is provided in FIG. 1. The system is implanted in a patient 10 with a canister 12 in the left axilla at about the level of the cardiac apex. A lead 14 is placed with a first portion extending subcutaneously along the inframammary crease to the xiphoid, and thence superiorly parallel to and 1-2 cm to the left of the sternum. A proximal sense electrode 16, shocking coil electrode 18, and distal tip sense electrode 20 are provided along the parasternal portion of the lead 14. The entire system is implanted outside of the ribcage. As shown in FIG. 2, a typical implant for the S-ICD System uses three incisions 30, 32, 34, and a sterile field represented by shape 36 shown is used to avoid the introduction of microorganisms that can cause infection. Some physicians have also used a two-incision technique foregoing the superior sternal incision 34.
The subcutaneous-only placement prevents some of the more dangerous complications associated with infection, in particular, endocarditis which can result when an infection travels down a transvenous lead into the heart. However, even with reasonable care, some patients will experience infection at the sternal incisions. In addition, some reports have shown that air pockets at either of incisions 32 or 34 can lead to inappropriate shocks within the first few weeks of implantation.
Alternatives to this implantation method are desired that would reduce the number of incisions.